Just in time for Easter, we have a movie about a young woman warrior possessed by a vaguely Christ-like extraterrestrial who bewitches a pair of smouldering hunks constantly debating whether to kill her or make out with her.

Andrew Niccol’s “The Host’’ — a long, tedious and often unintentionally hilarious adaptation of Stephenie Meyer’s sci-fi follow-up to her fantastically popular “Twilight’’ Trilogy — is set in a future where alien conquerors have banished disease, violence and pollution — but not visible panty lines. (They’ve also brought back generic-brand groceries.)

The anemone-like creatures use humans as their hosts, but like many things in this silly and lumbering movie, this doesn’t always work as planned.

When a human resister named Melanie (Saoirse Ronan) is captured, and her body is implanted with the soul of an anemone-like creature named The Wanderer, the strong-willed young woman begins fighting the creature over control.

Soon the two of them (in one body) flee Louisiana (and its production tax breaks) for Utah’s Monument Valley, while being pursued by The Seeker (Diane Kruger), who has those panty lines and is always making pronouncements like, “We’ve opened up a new planet.’’

There, The Wanderer — recognizable as a possessed former human because she has glassy eyes — meets up with Melanie’s uncle (William Hurt), who is supervising a wheat harvest inside a dormant volcano.

The uncle — who shortens The Wanderer to Wanda — is convinced that his niece is lurking somewhere in her body (Her grouchy aunt, played by Frances Fisher, is understandably skeptical).

In a concept that surely worked better on the printed page, The Wanderer is constantly arguing with Melanie’s voice.

Most of the Wanda/Melanie debate concerns Melanie’s boyfriend Jared (Max Irons) and the more hot-headed Ian (Jake Abel), who develops a love-hate relationship with her alter ego, Wanda.

Well, The Seeker did warn Wanda that “unlike the other bodies you have inhabited [humans] do have unusually strong physical desires!” Not exactly true from the evidence here.

“WANDA, NO!’’ Melanie’s voice exclaims when her former body has a a relatively chaste smooch with Jake. “THIS IS SO WRONG! YOU’RE NOT EVEN FROM THE SAME PLANET!”

There’s lots more where that came from, but not nearly enough laughs to sustain a two-hour movie where the extraterrestrials’ devotion to nonviolence severely limits the possibilities for dramatic conflict.

“What’s it like — the two of you living in there together,’’ one of the confused hunks asks Wanda at one point.

“Crowded,’’ Wanda replies.

“The Host,’’ on the other hand, is pretty consistently empty-headed throughout.